As one crosses the plains in the vicinity of Tilrempt he notes the scantiness of the vegetation. (See fig. 9.) Here and there in the depressions are a few betoums, often only one specimen, but usually more, and in the erosion channels leading to the dayas is a sparse population of low, gray shrubs. Over the higher portions of the plain, one is aware that small perennials, 20 to 30 cm. high, are widely scattered, but it is the bare ground which gives the character to the landscape. Among other forms are species of _Aristida_ and _Stipa_, _Anabasis_ and _Haloxylon_, with dwarfed specimens of _Zizyphus lotus_ in the washes near the dayas. The leading species, _Haloxylon articulatum_, is much eaten by the flocks of sheep and goats (over 7,000 sheep are said to obtain water at the daya), but occasionally it is present in surprising numbers. For example, on a slope to the northeast of the daya, and but a few meters distant, 227 living specimens of _Haloxylon_ were counted on an area of 16 meters square; in another place, near the crest of a low hill to the west of Tilrempt, where the conditions were probably as unfavorable as any in the region, 118 specimens were found on an area of the same size. In both squares there appeared to be no other species present. Tilrempt is said to contain 2,400 betoum trees, although the visitor would not be likely to estimate the number at nearly so high a figure.[15] Numerous specimens of jujube are also scattered through the daya, with some _Peganum harmala_ and _Francœuria crispa_. As a person visits the floor of the daya he is struck by the great beauty of the betoums. They are of a compact habit of growth, shapely, and cast a dense shade, an unusual feature in a desert tree. Attaining a height of 15 meters or more, the tree may have a spread equaling or exceeding this amount. The bole of the largest specimens is of large size; one was found 4.56 meters in circumference, another 4 meters, while a third measured 3.36 meters. All measurements were made 1 meter from the surface of the ground. No betoums, however, were seen to have developed in a perfectly normal way, and this observation applies not only to Tilrempt but to all other dayas seen, but they were disfigured in a peculiar manner, the lower branches giving the appearance of having been cut and removed at a height of 2.85 meters. In fact, this had been done, and the lowest existing branches marked the highest point to which a browsing camel can reach. The leaves of the betoum are compound, consisting of 7 to 9 large leaflets. The branches are unarmed and the twigs, younger branches, and leaves are eagerly eaten by whatever herbivorous animals can reach them. (Fig. 12.) So much is the betoum sought after as a food that it would be exterminated if it were not protected by another plant, namely, the jujube.[16] The character of the leaves and young shoots of the betoum may be seen in fig. 15.